Injection pump control



v s. MEISWINKEL 2,244,306

INJECTION PUMP CONTROL Filed March 14, 1938 Patented June 3, 1941 INJECTION PUMP CONTROL Samuel Meiswink el, Gaggenau, Baden, Germany, assignor to Daimler-Benz Aktiengesellscliaft, Stuttgart-Unterturkheim, Germany, a company of Germany Application March 14, 1938, Serial No. 195,853 In Germany March 15, 1937 12 Claims.

This invention relates to an improved injection pump control, and is particularly concerned with fuel-injection pumps for'multi-cyllnder internal combustion engines. In these latter, a number of pump pistons corresponding to the number 01' engine cylinders are generally disposed side by side in a row in a common housing and the control of the quantity injected is efl'ected by hand or by means of a regulator dependent upon a function of the internal combustion engine, through a common rack which turns gear wheels provided on the piston guides. By this means the pistons are turned so that control edges thereon are appropriately adjusted in relation to i'uel supply ports or orifices.

Before exercising such a common control of all the pump pistons by displacing the rack, it is necessary to be able to adjust each pumppiston 1 by itself. I

One object of the invention is to provide a number of individual rack sections engaging the gear wheels of the pump pistons, said sections being mounted upon a control bar in such fashion as to be displaceable' in order to permit of both an individual adjustment and also a commonadjustment of the pump pistons.- The control bar may be provided with an external thread and may carry a number 01' bushes which are provided with external teeth and which mesh with the gear wheels on the pistons, the wheels being maintained in their position of engagement by means of spring force. These wheels are accessible from outside by means of a suitable tool, so that they can be moved at will out of engagement with the 1 toothed sections, thereby enabling the latter to be slid along the control bar. I

In comparison with known individual adjustment arrangements, an arrangement in accordproved injection pump comprising two pump pistons;

Fig. 2 is an end viewtof a detail seen in the direction of the arrow a in Fig. 1;

Fig. 3 a vertical section on the line II in Fig. 1;

Fig. 4 is a horizontal section of a second example;

Fig. 5 is a vertical section on the line II-H in Figure 4; and

Fig. 6 is a view on an enlarged scale of a screw plug as used in the second example.

In both examples, two pump pistons 2 are disposed side by side in a common housing I. The lower part of each pump piston has two guide grooves 8 located one opposite the other, and below the grooves, is reduced to form a stem 4 which is enlarged at its lower end to form a rounded button 5 for engagement with an operating cam 6. Over the grooved part of each piston is slipped a gear wheel I having-a downwardly projecting collar 8. Abutment collars9 are slipped over these collars and, engage the ends of compresison springs III. The lower ends of the springs Ill abut against the buttons 5 on the stems 4. The springs I0 thus press. the buttons- 5 against the cams 6 and also press the wheels I against plane abutments on the housing I. The cam shaft 21 is .mounted in the lower part 26 of the housing.

Each gear wheel I meshes with a respective sleeve II provided with external teeth and the two sleeves-are mounted by threads on a control bar I2. Referring to Figures 1 to 3, each sleeve ance with the invention has the advantage that the position of the adjusting members is not changed by the impulsive loading of the piston and its stem such as occurs in a pumping operation. By this means, these adjusting membersnever become loose or so tight that they cannot subsequently be released. Also the adjustment of the quantity supplied is simpler with the arrangement according to the invention, and the adjusting members do not need to be made as strong as was hitherto necessary. Consequently they can be made lighter, which also represents a saving of material. I

The invention is illustrated in two constructional examples in the drawing, in which:

Fig. 1 is a horizontal section through an im is formed with several longitudinal grooves I3,

four being shown in Fig. 3. The plates 9 project into grooves I3 adjacent to the gear wheels I, and thus prevent turning of the toothed bushes II whilst permitting them to slide. In order to give the sleeves a better hold, the edges of the plates 9 may be bent down at right angles as shown. The control bar I2 is mounted in the housing I in longitudinally displaceable fashion by means of screw sleeves I4 (Fig. 1), and is pre vented from rotating by a transverse pin I5. The pin I 5 slides in notches Ila provided in an extension of one of the screw caps ll (Figs. 1 and 2). Finally, openings I6, II are provided opposite to each other and at the same level on both sides of the pump housing at the level of the rings of teeth 01' the wheels I, and the wheels I and toothed sleeves II are thus rendered accessible from outside.

In Figs. 4-6 an opening I! is formed at one side only, and there is screwed into such opening a screw plug having a projection 24 for engaging in one or other of the grooves l3a, formed in the sleeves H.

The operation is as follows:

The cams 6 lift the pistons 2 against the resistance of the springs Ill. The fuel is drawn in from the supply I8 (Fig. 3), and is forced out through delivery passages IS. The quantity supplied at any time is .controlled by the amount of port opening uncovered by the control edges 20 of the pistons 2. As will be seen from Figure 3, the control edges 20 are inclined and work in conjunction with ports 2| communicating with the supply IB. The size of the port openings released depends upon the angular position of the pistons 2 in relation to the ports 2 I.

The common control of all the pump pistons is effected in known manner by means of a regulator, not seen in the drawing, which is preferably dependent upon the revolution speed of the internal combustion engine and which displaces the control spindle l2 axially together with the toothed sleeves ll mounted thereon. The gear wheels I are turned by the axial displacement and they turn the pistons 2 by means of the groove guide engagement 3. By this means, also, the

control edges 20 are adjusted in relation to the ports 2| and the quantity of liquid flowing into the pump space is increased or reduced depending upon the direction of rotation of the adjustment.

The individual adjustment of the pistons is effected according to the invention by an appropriate angular adjustment of the pistons. For this purpose, the gear wheel 1 of the piston 2 to be adjusted is displaced downwardly by means of a pointed fiat pin 22, shown by a chain-line in Fig. 3. This depression of a wheel is effected against resistance of the spring l0, until the said wheel comes out of mesh with its respective toothed sleeve H. In this position, the toothed sleeve II can be turned upon the spindle I2 through any desired angle and thereby be displaced axially by the desired amount. Furthermore, in this lowered position, the gear wheel I also can be turned with the piston 2 through any desired angle for adjustment of the control edges 20. When this has been done, the wheel I is released by the tool 22 and it moves back upwardly into meshing position under the influence of the expanding spring Hi. If desired, the tool 22 may be inserted and operated merely for depressing an abutment plate 9. This frees the corresponding toothed sleeve ll so that the latter can be adjusted along the spindle 12. The nature of the teeth on the toothed sleeves H and on the gear wheels 1 may, within the scope of the invention, be as desired. Also, within the scope of the invention, it is immaterial whether the guide grooves for the pump pistons 2 are provided in the wheel bodies 1 or on the piston stem, or whether the pistons 2 are guided directly in the gear wheels 1 or slide in intermediate bushes carried along by the gear wheels I. Preferably, the plates 9 have straight guide edges on their side towards the grooves l3 of the toothed sleeves. Also, within the scope of the invention, the number of guide grooves l3 on the toothed bushes may be as desired. In some cases, spring members secured to the housing I project as stops for the toothed bushes I I. An appropriate application of the invention also results when sleeves or rack sections merely slide upon a smooth control bar-and are secured by the pressure of spring clasps coacting in some cases with notches. The improved pumps are suitable for the injection of water into the combustion spaces of internal combustion engines and can also be employed likewise wherever a precisely proportioned quantity of liquid to be supplied is required.

For certain cases, it may be preferable to give the control bar l2 a tendency to move towards a definite end position. This may be effected, for example, by a spring 28 inserted in the intermediate space 23 (Fig. 1). If the spring is so arranged that it forces the control bar, for example, into the idle running position, then running of the engine to destruction is reliably prevented thereby. In similar fashion the pumps may be set for any desired preferred output to be supplied. Also, in certain cases, a construction may suffice wherein the rack continues in the usual fashion as a unitary whole, and the adjustment of the wheels at the pistons is effected by bringing these wheels out of engagement and turning in this position. Also, within the scope of the invention, it is possible to hold the wheels I in the position of engagement by springs, attached to the housing, which do not partake in the piston movement,

In Figs. 4-6, for the purpose of angular adjust ment of the pistons, the screw plugs 25 are unscrewed and removed. This gives access to the sleeves I l and also releases them by withdrawing the projections 24 of the plugs 25 from the grooves 13a of such sleeves. Thereupon the latter can be turned for performing the desired adjustment. By lateral displacement of the sleeves H, it is also possible to take them out of mesh with respective gear wheels, whereupon the latter can be turned through a desired angle by means of a tool. When this has been done, the meshing is reestablished, and the screw plug 25 is screwed in again.

It will be seen therefore that I have provided a device which fulfills the objects primarily stated, and while I have shown two embodiments of my invention, it is clear that other forms thereof may readily be provided without departing from my invention as defined in the claims which follow.

I claim:

1. In a liquid injecting pump comprising a plurality of reciprocatory pistons with variable delivery obtained by rotary adjustment of the pistons, the combination of gear wheels slidable but non-rotatable on the pistons, springs intermedb ate said gear wheels and pistons for urging the former to a normal predetermined position relatively to the latter abutment plates for said springs, an axially displaceable control bar having an external screw thread, and rack sections screwable along said control bar, said rack sections having external longitudinal grooves for engagement with said abutment plate.

2. In a liquid injecting pump comprising a plurality of reciprocatory pistons with variable delivery obtained by rotary adjustment of the pistons, the combination of gear wheels non-rotatably mounted on the pistons, an axially displaceable externally threaded control bar, a plurality of sleeves threaded on said control bar and individually adjustable along the latter by turning, said sleeves having teeth extending about their circumferences interrupted by spaced external longitudinal grooves and meshing with said gear wheels, and removable stop means having engagement in said grooves to prevent said sleeves from turning.

3. In a liquid injecting pump having a housing provided with a plurality of apertures comprising a plurality of reciprocatory pistons with variable delivery obtained by rotary adjustment of the pistons, the combination. of gear wheels slidable but non-rotatable on the pistons, stops on said pistons, springs pressing said gear wheels against said stops on said pistons, an axially displaceable control bar. and rack sections adjustable along said control bar and meshing with said gear wheels, sai-d gear wheels being normally disposed opposite apertures in the pump housing, whereby access can be had to such gear wheels for depressing them out of mesh with the rack sections and against the resistance of the springs.

4. In a liquid injecting pump comprising a plurality of reciprocatory pistons with variable delivery obtained by rotary adjustment of the pistons, the combination of gear wheels slidable but non-rotatable on the pistons, springs operative for holding said gear wheels in position, an axially displaceable control barhaving external screw threading, slideways for said bar in which the Patter can slide but not turn, and rack sections screwable along said control bar and in mesh with said gear wheels.

5. In a liquid injecting pu'mp comprising a plurality of reciprocatory pistons with variable delivery obtained by rotary adjustment of the pistons, the combination of gear wheels slidable but non-rotatable on the pistons, springs operative for holding said gear wheels in position, an axially displaceable control bar having external screw threading, slideways for said bar in which the latter can slide but not turn, rack sections screwable along said control bar and in meshwith said gear wheels, and means on said bar for connecting it with the governor of an internal combustion engine.

6. In a liquid injecting pump comprising a plurality of reciprocatory pistons with variable delivery obtained by rotary adjustment of the pistons, the combination of gear wheels slidable but non-rotatable on the pistons, springs operative for holding said gear wheels in position, an axially displaceable control bar having external screw threading, slideways for said bar in which the latter can slide but not turn, rack sections screwable along said control bar and in mesh with said gear wheels, and spring means constantly influencing said bar towards one end position.

7. In a liquid injecting pump having a casing provided with a plurality of threaded holes, comprising a plurality of reciprocatory pistons with variable delivery obtained by rotary adjustment of the pistons, the combination of gear wheels non-rotatably mounted on the pistons, an axially 8. In multi-piston liquid injection pumps in which variable delivery is obtained by rotary adjustment of the pistons, the latter being adjustable in unison by rack and pinion transmission, the combination of individually adjustable rack sections, pinions movable out of mesh with respective rack'sections, and withdrawable stop means normally holding the rack sections in adjusted positions. I

9. In a liquid injection pump comprising a '.plurality' of reciprocatory pistons with variable delivery obtained by rotary adjustment of the pistons, the combination of gear wheels on said" pistons, an axially displaceable control bar, circular rack sections having teeth extending about their circumference, rotatably adjustable along said control bar and meshing withv said gear wheels, and removable stop means for preventing said rack sections from turning.

10. In a pump having a plurality of displaceable pistons provided with variable cut-oft positions, gear wheels slidably mounted on each piston, an axially movable control rod, rack sections having teeth extending about their circumferences, individually threadably mounted on said control rod and engaging the respective gear wheels on said pistons, whereby movement of said control rod rotates said gear wheel to simultaneously vary the cut-off of all of said piston: and individual rotation of each rack section on said control rod varies the cut-ofl" of individual pistons, and control means for varying the initial set and range of movement of said control rod.

11. In a pump having a plurality of displaceable pistons provided with a variable effective delivery stroke, gear wheels slidably mounted on each piston, an axially movable control rod, rack sections threadably mounted on said control rod and engaging the respective gear wheels on said pistons, and removable means for holding said rack sections against rotation on said control rod.

12. The combination according to claim 12 in which said removable means includes a spring abutment slidably mounted on said piston, in combination with means for displacing said piston, and a spring intermediate said abutment and one end of said piston for urging the latter into contact with the piston displacing means.

SAMUEL MEISWINKEL. 

